# -*- coding: utf-8 -*- 
# @File : Stack.py
# @Time : 2019/10/17 22:28 
# @Author : yaozi
# @Contact : xt1512326654@sina.cn
class Stack:
    def __init__(self):
        self.item = []

    def push(self, item):
        self.item.append(item)

    def pop(self):
        return self.item.pop()

    def is_empty(self):
        return self.item == []

    def peek(self):
        return self.item[-1]

    def peek(self):
        return self.item[-1]

    def size(self):
        return len(self.item)
